There are a numerous of digital communication systems being operated in the world. For instance, Private Mobile Radio, Pulse Code Modulation, Tetra and Digital Audio Broadcasting(DAB), all with advantages and disadvantages when compared to each other. This Technical report is aiming on the wireless technology which people started using in The 21st century known as the ZigBee. The ZigBee wireless technology has been manufactured and approved by the member companies of the ZigBee Alliance.
There is a global expansion in the use of electronic devices. Mostly, these electronic devices requires the connection between them using electrical cables. The ZigBee wireless technology is a method that is implemented to connect the electronic devices without the use of cables, and thus the wireless connections.
The aim of this technical report is on the wireless technology called ZigBe. The advantages and disadvantages of using ZigBee wireless technology are examined, also observing the future improvement of this wireless technology. Moving on, the investigations and examination of topics such as the wireless technology's operations and functionalities and why this type of communication technology is being chosen by people around the world will be carried out. Adding to that, as well as making technical analysis on a number of topics and sub-topics, the technical report will also discuss the limitations of the wireless technology .
Definition of ZigBee Wireless Technology
The wireless technology known as ZigBee was first introduced to the general public in the 21st century. The wireless technology was fabricated and ratified by the member companies of the ZigBee Alliance.
The ZigBee wireless technology is centered on the concept that the electronic devices connection and communication between them is carried out without the employment of connection cable wires, for that reason we thus have the word wireless technology. Also, ZigBee is the name for a PAN network technology and wireless technology that is centered on the IEE standard 802.15.4. It operates low speed data in the ISM UHF and low microwaves bands to implement monitor and control functions over short distances in houses, commercial and industrial applications. It is mainly centered on the concept of mesh networks.
Topology of ZigBee′s Mesh Network
http://www2.renesas.com/magazine/en/vol_0073/vol_0073_1.html
The use of this type of technology is very noticeable in a numerous fashions in our everyday lives. For instance, when individuals operate telecommunication electronic devices such as mobile phones and wireless headsets, handheld electronic devices, when key-boards are united to PCs (personal computers) without the utilization of electrical cable wires and MP3 players with no headsets, all this is ZigBee wireless technology.
The ZigBee enabled electronic devices recognizes each other and immediately, they automatically synch up and a wireless network is thus patterned.
Electronic devices that are ZigBee enabled are embedded with tiny, low-powered radios embedded on an electronic chip that guarantees the possibility of transmitting and receiving voice and data communication from other ZigBee enabled electronic devices.
Finally, ZigBee is created to be used in the license-free spectrum accessible in the world.
Main Reasons The Communication System Was Introduced
ZigBee Electronic Communication Devices Are Wireless
One of the major advantages of working with ZigBee is that it uses wireless technology. The getting rid of the use of cable wires makes it simpler and easier for individuals to work with their easily transported electronic devices such as laptops without the difficulty of having cable wires. Moreover, the safety of the individual is improved as cable wires are potentially an electrical danger. The ZigBee communication system is good to the user's economy as it saves him/her some cash as the user can use some electronic devices without the requirement of purchasing electrical cable wires.
ZigBee Communication System Is Automatic
This kind of technology does not need the individual to carry out performance for setup. All what is needed is that the ZigBee operators to be close to each each other, in a certain proximity, they automatically link up, ready to communicate. Personal Area Networks are produced when the electronic devices commence the communication procedure. Adding to that, PANs are also known as the piconets.
No set-up linking and connection required to be carried out.
ZigBee Communication System Connect More Electronic Devices At A Time
A number of electronic devices can be linked together with a certain range of proximity. The linkage takes place when there is the presence of piconets establishments or the PAN (Personal Area Networks).
ZigBee Communication Technology Has Low Energy(Power) Consumption
ZigBee electronic devices operate by implementing a low power electrical signals, this allows them utilize less electrical energy and electrical power. This is good for the operator's economy as it allows him/her to saves some cash and this technology can also be seen an advantage in terms of fighting against global warming.
This is also a huge advantage for mobile devices as the battery life will not be drained by the ZigBee electronic communication device, and thus can retain energy for longer periods.
ZigBee Communication Technology Has Low Interference
Despite the fact that the ZigBee system of communication functions in a frequency range that is used in common with a lot of other electronic devices ISM Band [industrial, scientific, etc] it is able to reduce the interference by a technique known as DSSS.
The Zigbee wireless technology operates DSSS [Direct Sequence Spread Spectrum], which divides the 2.402 - 2.480 GHz [Giga Hertz] spectrum into 16 channels or 10 channels in the 915 MHz [Mega Hertz] spectrum and 1 channel in the European 868 MHz spectrum.
Operating the technique called Direct Sequence Spread Spectrum signifies that although they are a lot of the electronic devices working in the ISM Band, ZigBee electronic devices are not actually influenced by interference.
More on the Spread Spectrum
The Spread-Spectrum methods are techniques whereby a signal (e.g. an electrical, electromagnetic, or acoustic signal) produced in a particular bandwidth is deliberately spread in the frequency domain, making in a signal that have a wider bandwidth. These methods are operated for a lot of the reasons, involving the creating of safe and protected communications, expanding resistance to natural interference and jamming, to avoid the detection, and to restrict the power flux density
ZigBee Communication System - Sharing Voice and Data
The ZigBee communication technology enables the electronic devices to exchange both voice and data. This allow users to exchange information using ZigBee electronic devices.
Also, voice and data can be exchanged easily between the compatible ZigBee devices. For instance, a mobile phone can be linked to a headset and exchange voice at the same time the mobile phone can be linked to a PC (personal computer) and be capable to connect and browse the internet via the ZigBee wireless communication technology.
ZigBee Communication System Is Relatively Cheaper
This kind of digital communication technology has lower costs for manufacturing companies when compared to other wireless technologies. The fabricating expenses that are handed over to the clients are less, and thus producing the overall resulting price generally inexpensive.
Tiny and low-powered radios(that guarantees the possibility of transmitting and receiving voice and data communication from other ZigBee enabled electronic devices.) embedded on the tiny electronic chips have a tiny small area factor, and thus allowing them to be fabricated inexpensively. ZigBee electronic chip is tiny and inexpensive enough to be assembled in mobile phones at a low price.
Secondly the ISM (Industrial, Scientific, etc) band that the ZigBee operates is unlicensed, and thus allowing it to be free to operate and is also operated by non-ZigBee communication systems.
Finally, the technology defined by the ZigBee specification is intended to be simpler and less expensive than other WPANs, such as Bluetooth. ZigBee is targeted at radio-frequency (RF) applications that need a low data rate, long battery life, and secure networking.
ZigBee Communication Technology Is Standardised
Standardized Protocol = Interoperability
Interoperability is a property referring to the ability of diverse systems to work together (inter-operate)
High compatibility of ZigBee communication device is available as ZigBee has a standardized wireless specification. The specification defines and operates various profiles. ZigBee electronic communication system devices with the similar profile link together. For instance, a mobile phone and headsets, as long they both obtain similar profile, they will be capable of communicating. Being of different models is not essential.
ZigBee Communication Technology has no Barriers
ZigBee communication system is not influenced by barriers such walls, as does the infrared that operates by line of sight, therefore does not function if there is a barrier.
ZigBee Communication Technology Is Upgradeable
The ZigBee communication (wireless) technology is upgradeable. ZigBee communication technology upgrading is performed as to create better versions of the digital communication technology.
The ZigBee Communication Technology is here to Stay
The ZigBee communication system is being operated worldwide. With that, it signify that this type of wireless technology will be around for countless number of years as the technology was and is a breakthrough for electronic industries, communication industries and information industries.
How ZigBee Wireless Technology Works and Technical Aspects of This Communication Technology
The ZigBee wireless technology which saw its use put to action in the 21st century. The wireless technology has been manufactured and approved by the member companies of the ZigBee Alliance. The ZigBee wireless technology is centered on the IEE standard 802.15.4. It manages low speed data in the ISM UHF and low microwaves bands to implement monitor and control functions over short distances in houses, commercial and industrial applications. This type of communication technology is mainly centered on the concept of star and mesh.
The 802.15.4 standard describes the so-called air interface, which is the physical layer(PHY or layer 1 of the OSI standard) and the media access control (MAC or layer 2) of the system. The ZigBee Alliance, an organization of chip, software, and equipment vendors of ZigBee products, outlines further higher levels of layers that involves the networking and the security.
Furthermore, the ZigBee wireless communication system is fabricated to work in the license-free spectrum that is accessible in the world.
There three known fundamental bands and versions
Frequency Band
Number of Channels
Modulation
Max. Data
Rate. Kbps
~ 860 MHz(in Europe)
1
DSSSS/BPSK
20
~ 900 MHz
1
DSSSS/BPSK
40
~ 2.5 GHz
16
DSSSS/O-QPSK
250
The fact that the data rates are relatives low is not of an issue because a lot of the applications are to transmit the sensor data or to simply apply on/off actions. The transmissions procedure are performed by the packets that have the greatest size of 128 bytes(1024 bits), 832 of which is the data itself. The 16-bit and the 64-bit addressing modes are all accessible, although the greatest is thought to be as high as 65 536 total nodes. Further more, the access technique is just like the Wi-Fi is CSMA/CA. The predominantly operated version is the one that is functioning in the ~ 2.5GHz band.
Moving on, the range changes with the application and the environment. When operating the ~ 2.5GHz, the usual greatest indoor range is roughly 3000 centmetres. The range can increase to 40000 centmetres outdoors.
The greatest range is attained at ~ 860 MHz or ~ 900MHz and this can be as high as ~ 1kilometres with a line-of-site footpath or road. The advantage and goodness of ZigBee technology is its adaptable and adjustable networking properties abilities.
The standard hold and sustain three known topologies:
Mesh
Star
Cluster Tree
http://www.microwatt.co.uk/services/wireless/
The topologies that are frequently operated are the star and the mesh.
The network topologies are composed of three kinds of ZigBee nodes:
A ZigBee(PAN) Coordinator
A ZigBee Router or the Full Function Device (FFD)
ZigBee End Device or the Reduced Function Device (RFD)
The ZigBee Coordinator begins the creation of the network. The Full Function Device functions as the monitor or the control device that monitors a sensor and implements off/on actions on some end device. Also, the Full Function Device functions as a router since it receives information from other nodes actually sends it to other nodes. The Reduced Function Device is the end monitor and the control device. It collects data and sends the data. The Reduced Function Device does not repeat and doesn't route.
The star configuration indicated in the diagram above, is one of the most common, where a the Full Function Device (FFD) receives the information from and hands out the control information to other ZigBee Routers and the Reduced Function Devices. The Full Function Device transmits data back to the ZigBee Coordinator that functions as the main controller for the system.
Moving on, in the mesh network system, a lot of the nodes are ZigBee Full Function Device or Routers that function as monitor and control points and they can repeat and route the information to and from other nodes.
The importance and advantages of the mesh network system is that the system can vastly expand the range of the network. In the situation that the node doesn't have the power to go to the wanted node, it is able to send its information through neighbouring nodes that will effectively move along the information until the wanted point is reached.
While the greatest range between the nodes can just be 30 metres, the range is increased by moving the information from node to node over a much expanded limits and wider area. Additionally, the ZigBee mesh is able of sustaining thousands of user nodes plus one fully functional device. Devices are optimized for expanded battery life.
Further characteristics and features that adds to the network system of mesh's advantages and importance is that the network is dependable. For instance, if a single node is not working, the information is still able to be routed through other nodes using alternate directions and ways.
With inessential paths back to the Full Function Device, a ZigBee mesh guarantees that the information reaches the location it was destined to in spite of the availability of the unwanted circumstances. A lot of applications need this type of standards of robustness.
Moving on, the ZigBee wireless technology means of digital communicating can address a broad area of wireless requirements. The digital communication technique/system was drafted essentially for monitoring and controlling. Monitoring is concerned with examining the wide range of physical circumstances, notably temperature, pressure, the availability of speed, light and position data. The sensors create an anolog electrical signal standing for the physical variable and the electrical signal is then amplified and then changed to digital information that is then sent back to the monitoring point.
This kind of feather enables the ZigBee wireless technology a greater short-range telemetry system. Telemetry system is whereby a communication system is operated for remote monitoring and measurements. Thus the ZigBee wireless technology is suitable in wireless sensor networks.
Uses Of The ZigBee Wireless Technology
Control is primarily concerned to the transmitting of command electrical signals to begin some intended activities. Usually, the commands are utilized to switch appliances off and on. For instance, lights, moors, solenoids, relays, and other devices that carries out some kind of function.
The Home Automation With ZigBee Wireles Technology
http://focus.ti.com/analog/docs/gencontent.tsp?familyId=367&genContentId=24190&DCMP=hpa_rf_general&HQS=NotApplicable+OT+zigbee
Famous uses involve monitoring and controlling lights, heating, and air conditioning; and industrial monitoring and controlling in manufacturing processes. Automatic electric and gas meter recording is a huge use of this wireless technology. Other uses of this kind of technology are found in the science of medicine such as wireless monitoring of a patient and in purchaser applications such as in home monitoring and control, remote control of other things, and security. As well, the ZigBee wireless technology is operated for the most part in the concentrators, data collectors, repeaters, and meters installed in the urban distribution AMR systems and prepayment systems.
The ZigBee wireless technology means of digital communication system is inexpensive and used using batteries. The technology can be operated in a various conditions.
Moreover, the wireless technology is aiming the control applications industries that don't need high data rates, and have low power, inexpensive and simple to operate.
The Protocol Architecture - The ZigBee Wireless Technology
The ZigBee Alliance produced the ZigBee device object (ZDO), the application support sublayer (APS), the network layer, and security management. The IEEE 802.15.4 is operated for the MAC layer and physical layer.
The ZigBee Protocol Architecture
http://ptgmedia.pearsoncmg.com/images/chap2_9780137134854/elementLinks/02fig06.jpg
Furthermore, the ZigBee protocol architecture is broken down into three portions, like this:
The IEEE 802.15.4, that comprises of the MAC and physical layers.
The ZigBee layers, that comprises of the network layer, the ZigBee device object (ZDO), the application sublayer, and security management.
The manufacturer application: The makers of the ZigBee devices can operate the ZigBee application profile or make their own application profile.
The Physical Layer
The physical layer carries out the modulation on outgoing electronic signals and demodulation on incoming electronic signals. It sends the data and collects data from a source.
The table below displays:
The physical layer frequency band
The data rate
And channel numbers.
Frequency Band
Country
Data Rate
Channel Numbers
868.3MHz
European countries
20Kbps
0
902-928 MHz
United States
40Kbps
1-10
2.405GHz
Worldwide
250Kbps
11-26
Physical Layer Frequency Band
The Media Access Control (MAC) Layer
The uses of the MAC layer are:
To access the network by operating the carrier-sense multiple access with collision avoidance (CSMA/CA)
To send beacon frames for synchronization
And to supply dependable transmission.
The Network Layer
The network layer is positioned between the MAC layer and application support sublayer. The network layer supplies the functions such as:
Initializing a network
Being in control of the end devices attaching or leaving a network
The discovery of the route
The discovery of the neighbour
The Application Support Sub-layer (APS)
The application support sublayer (APS) supplies the services that are required by the application objects (endpoints) and the ZigBee device object (ZDO) to blend with the network layer for information and management services.
Moreover, parts of the services supplied by the APS to the application objects for information transmission are:
Request
Confirm
And response
The APS supplies the communication for applications by defining a unified communication structure such as:
A profile
Cluster
Or endpoint
i) The application object (endpoint): The application object defines input and output to the APS. For instance, a switch that regulates a light is the input from the application object, and the output is the light bulb condition. Every node can have 240 individual application objects. Moreover, the application object can be referred to as an endpoint (EP).
The figure below indicates an example of home control lighting.
The Home Control Lighting
http://ptgmedia.pearsoncmg.com/images/chap2_9780137134854/elementLinks/02fig07.jpg
ii) The ZigBee device object (ZDO): The ZigBee device object carries out the regulation and management of application objects. Also, the ZDO carries out the overall device management works:
Decides the kind of device in a network. For instance, end device, router, or coordinator.
Starts the APS, the network layer, and the security service supplier
Carries out the device and service discoveries
Starts the coordinator for implementing the network
The security management
The network management
The binding management
iii) The End node: Every end node or end device can have numerous EPs. Every EP have an application profile, like home automation, and can be operated to regulate numerous devices.
Furthermore, every EP defines the communication functions that are found in the device being worked with. As indicated in the figure above, the bedroom switch regulates the bedroom lighting systems, and the remote control is operated on in order to regulate the three lights:
The bedroom
The hallway1
And hallway2
iv) The ZigBee addressing mode: The ZigBee operates direct, group, and broadcast addressing for sending the data.
In direct addressing, the devices exchange information directly amongst themselves.
The Group addressing requires that the application assign a group membership to a single or a lot of the electronic devices. Furthermore, the packet is then sent to the group address in which the destination device is located.Also, the broadcast address is operated to transmit the packet to all devices that are found in the network.
More On The Protocol Architecture - The ZigBee Wireless Technology
The ZigBee and the ZigBee Pro Feature Sets
A few years ago, the ZigBee Alliance established 2 feature set specifications for the ZigBee:
- ZigBee
- ZigBee PRO
The ZigBee PRO presents quite a number of noticeable improvements, notably, the security and the ability to self-form and self-heal the network. The new additional features are specially meant for operation in building automations and environmental and industrial applications that comprises of a lot of nodes. For instance, > 30 nodes.
Moreover, the ZigBee PRO is mainly centred on the concept of the mesh topology and is also a beaconless network. The characteristics of the ZigBee PRO are:
- The Addressing: The ZigBee PRO operates a mesh topology. Any device connecting the network needs a network address. The ZigBee PRO operates a stochastic addressing technique, and that means that a ZigBee device randomly selects an address when connecting the network. The device makes known its address on the network by operating the device-annc command. The ZigBee network layer supplies the address conflict resolution that is centred on the MAC address in the situation when two nodes have similar network addresses.
- The Link management: In the concept of the mesh topology, every node can exchange information with its neighbor. Also the node has the capability to evaluate the quality of its neighbor's links and to pick the best one for transmission of the packet.
- The Frequency agility: The ZigBee PRO picks the best channel that is present during the start-up of a network but, during the period when the network is working, in the situation that the node picks up the interference that has been made available because of the fact of the presence of the frequency conflict or the noise, it will then announce the development to the channel manager. Moreover, when the channel manger gets hold of the reports from numerous nodes on the network, it picks another channel for network operation and tells the nodes of the switch.
- The Group addressing: The ZigBee PRO supplies the group addressing; each packet is able to reach a group or a number of the devices.
- The Commissioning: It is a tool that is operated on by the ZigBee device installer to install the ZigBee devices.
- The Compatibility: The ZigBee PRO stack identifier is two and the stack identifier is advertised in the beacon frame. Furthermore, any end device is able connect the ZigBee PRO only if it operates the standard security mode.
- The Asymmetric link: The link between two nodes is frequently asymmetric, and that means that the quality of the link in both directions is not similar.
Asymmetric link
http://ptgmedia.pearsoncmg.com/images/chap2_9780137134854/elementLinks/02fig08.jpg
The link cost from node A to node B is not the same as the node from B to A (asymmetric link). This is so, because node A and node B do not have similar transmission powers and receiver sensitivities. In the situation that the node A and node E operate the similar route B-D to interchange the data, it is thus said symmetric.
When operating the asymmetric routing, the destination node operates a different path to send to the source. In the diagram above, the source (node) A operate the B-D path to transmit a packet to E, and E operate the path C to transmit the packet to A.
- The Fragmentation: The ZigBee PRO supplies the process of breaking down the big packets into tiny packets for sending. Also, the destination node will reassemble the packets
- The Power management: In ZigBee PRO, only the end devices are operated by batteries; the routers and coordinator operate main power. The ZigBee PRO permits end devices to go into sleep mode in order for them to use up less power. When the end device is in sleep mode, the node will loose network updates that are supplied by the trust center. When the device is not in sleep mode, it operates its link key to transmit message to the trust center to attain an updated network key.
- The Routing: The ZigBee PRO presents two kinds of routing: many-to-one routing and multicast routing. Many-to-one routing is operated for the network that have a concentrator.
- The Security: The ZigBee PRO presents two security modes, such as:
i) Standard mode: In standard mode, the device is allowed to operate the network key and link key. The network key is a standard key and all devices share the similar key. In this mode, devices do not need authentication to connect a network. Furthermore, the trust center, master key, and SKKE are available at choice. The trust center for ZigBee PRO standard security mode is operated for transfering the network key.
ii) High-security mode: In this mode, three keys are allowed for operation:
The network
The link
and The master keys
The trust center and SKKE are required. The trust center operates the transport key command to transfer the link and network keys to the devices in the network. The device is needed to carry out the authentication with the parent, and it is also needed to carry out the authentication between the available neighbors.
- Trust center: The ZigBee PRO is ought to have the trust center; the trust center may possibly be a router, coordinator, concentrator, or even be a specific device.
The Table below displays a Comparison of ZigBee 2006 Specification, ZigBee, and ZigBee PRO feature sets.
The Comparison of 2006 Specification, ZigBee, and ZigBee PRO Feature Sets
The ZigBee Features
The 2006 Specification
The ZigBee Feature Set Specification
The ZigBee PRO Feature Set Specification
Network coordinator selects best channel at startup.
Yes
Yes
Yes
During operation can detect interference and change channel operation.
No
Yes
Yes
Distributed address assignment.fd
Yes
Yes
Stochastic address assignment.
No
No
Yes
Supports group addressing.
Yes
Yes
Yes
Many-to-one routing.
No
No
Yes
128-bit Advanced Encryption Standard (AES) with message integrity code (MIC).
Yes
Yes
Yes
The ZigBee Wireless Technology Security
The ZigBee design goals answer questions such as:
What to secure?
Who to secure against?
How much security?
The Security Scope of the ZigBee design are:
Packet security
Key setup and maintenance
Because the ZigBee electronic devices are:
centred on small microcontrollers
have small memory
utilized in home/industrial type of situation
We thus are required to ensure that:
data is simple to implement and execute
low overhead for key storage and maintenance
flexible enough to sustain home and industrial usage
Moving on, the ZigBee Security does the following:
It explains Key setup and maintenance
Specifies Key Types (Master, Link, Network)
CCM* (Unified/Simpler mode of operation)
Furthermore, the ZigBee Security operates 128-bit AES algorithm Strong, NIST approved security.
Also, the ZigBee operates the fundamental security elements in 802.15.4 .
The 802.15.4 Security:
AES encryption
CCM security modes
The Infrastructure Security
The network access control
The integrity of packet routing
Avoids prohibited usage of the packet transport
The application data security
Message integrity (prevents the message from being altered in transit)
Authentication (supplies assurance on the originator of the message)
Freshness (avoids replay attacks)
Privacy (avoids an eavesdropper from listening the messages)
The operator will be secured against:
The outsider attacks
trust all devices in the network
Insider attacks as well
prevent data from other devices on network
ideal for circumstances when the devices require to operate some other network for transport.
The level of the Security
Flexible
Real cost vs. Security trade-off is configurable by the application
The memory constraints
the quantity of the keys and the associated data can we store.
Overhead
Additional bytes added to every packet
The security-specific signalling packets
In the situation that the electronic device is attaches, it ought to be admitted in the network. All the devices share the common network key. Furthermore, any two devices may share a link key. The key management (the key-transport, key-update) is carried out by the Trust Centre device.
The Key Types
The Network Key
The shared key, the basis of network-wide security, prevents infrastructure and application data from the outside r attacks.
The Master Key
The basis for the long-term security between the two devices
The Link Key
The basis of security between the two devices (the insider protection)
Brief Summary
The keys can be factory-installed or setup over the air or operating out-of-band mechanisms (eavesdropping ought to be avoided when this is setup)
The link and network can be updated regulary
The Trust Center
The Manager
Authenticate devices that asks to join the network
The Network Manager
Sustains and delivers network keys
The Configuration Manager
Allows end-to-end security between devices by assisting in setup of link keys
Could be on Coordinator or a dedicated commissioning tool
The Application-specific
Out of band techniques for the key setup
Cost/Security trade-off for number of link keys required
Policy for expiration and update of the keys
Policy for accepting the new devices
The Implementation Differences
The random number generator
If not truly random, encryption primitive is not secure
The hardware support
CCM and/or AES engine
The random bits
The handling of the error conditions
The loss of key sync etc.
Checking input sizes before processing
Buffer over/under flow attacks
A lot of the security attacks are caused by the flaws and defect that are present in the implementation.
The ZigBee wireless technology
The Disadvantages
The ZigBee wireless technology is a two-way wireless communication technology that have the following characteristics:
short distance/range
low complexity
low power consumption
low data speed
Adding to that, this form of wireless technology is operated frequently in data exchange amongst the low power electronic devices that are within a short range.
The Advantages
The foremost advantages of the ZigBee wireless technology are:
Ease of use
The power saving. This is the result of:
the short working period
low power usage of communication
and standby mode
The reliability. The collision prevention is implemented, with a special time slot assigned for those communications that require the fixed bandwidth in order for the competition and opposition to be prevented when sending the information.
The low cost of the modules
The ZigBee protocol is patent fee free
The short time delay.
Large network capacity. A single ZigBee wireless network comprises of one master device and a greatest 254 slave devices. Furthermore, there can a lot of the ZigBee wireless networks within one area
The safety. The ZigBee wireless network and technology supplies a data integrity check and authentication function. AES-128 is maintained and at the same time every application can flexibly decide its safety property.
Additionally, the ZigBee mesh is able of sustaining thousands of client nodes and one fully functional device (master). The devices are optimized for the long battery life, calculated in months to years, from inexpensive, off-the-shelf non-rechargeable batteries.
The Limitations Of The ZigBee Wireless Networking and Technology
The ZigBee wireless technology form of digital communication experiences some limitations. Amongst the types of the limitations are the technical points like:
the low data rate
the low power networking technical know-how for the short distance communications
the ZigBee networking layer protocols are carried out on the single M16C microprocessor
the transport layer functionalities like the fragmentation and reassembly are carried out at the application layer, as the ZigBee networking does not contain the fragmentation support
the multiple access scheme is CSMA/CA, therefore just the finest effort multi-hop transferring of JPEG and JPEG-2000 images are put to the tested and analysed.
the short range
the low complexity
The ZigBee Wireless Technology
The Future Improvements
The ZigBee wireless technology is quite a newly introduced wireless standard based on IEEE 802.15.4 for Personal Area Networks (PANs).
The routing protocol of the ZigBee operates a modified AODV by default and Hierarchical Tree Routing as the last resort. To begin with, both the algorithms (AODV and Hierarchical Tree Routing) are compared in terms of the delay performance and usage of the energy. The outcome results indicates that the Hierarchical Tree Routing supplies smaller average end to end delay but carries out the task insufficiently in terms of the energy usage.
It now stands out that, for sustaining the real-time communication, is it favourable to, at will, select one or another with consideration to the kind of the traffic, thus real-time and non real-time. Subsequently, the Hierarchical Tree Routing algorithm is altered slightly in order to supply lesser delays than the original one.
The ZigBee wireless technology can be further improved so that the future usage of the networking technology can be satisfying and very entertaining.
In the ZigBee networking technology form of the digital communication system the technique for high-speed transmission and reception are ought to be supplied. With that in mind, it stand to be very reasonable to suggest that the the improvements of the ZigBee wireless technology in order to increase and advance its performance, the expansion of reception mechanism is quintessential.
Moving on, the ZigBee system/network consists of the controller, the first transmission unit, and a second transmission unit. The controller outputs a first control signal that manages the high-speed transmission and a second control signal that governs the general transmission. The first transmission unit sends the information at high speed when receiving the first control signal. The second transmission unit sends the information at general speed when receiving the second control signal.
This kind of the networking technology can be enhanced by maximizing the data transfer rate from the present one. Moreover, the devices that operate the ZigBee wireless technology are ought to be fabricated in such a way that they should be exposed (antenna) and investigations must be implemented to ensure that there is no interference from the other ZigBee devices. Additionally, the material that cover the antenna must, with care, be selected in such a way as to maximize the reception, and decreasing the time of the ZigBee wireless connection by speeding up the inquiry state procedure.
Also, the networking technology can be updated and improved by paying attention on the security features. It is unsafe and not secure to send the data that is highly and greatly confidential due to the chances of the data being interfered with and distracted, for instance, this can apply to the financial data.
Summary
The above examined Protocol Architecture of the ZigBee wireless technology illustrated a general overview of ZigBee wireless technology, the ZigBee wireless technology applications, and the ZigBee wireless technology features. Below are the essential concepts that were clarified in respect to the ZigBee protocol architecture.
The ZigBee, a wireless sensor and control network, was established by the ZigBee Alliance.
The ZigBee applications can be operated in home automation, commercial building automation, personal home health care, smart energy, and industrial process monitoring. The first ZigBee specification was developed in the early 21st century and supported the home control lighting; the ZigBee Alliance no longer sustains the 2004 specification.
In the year 2006, the ZigBee Alliance establied the ZigBee 2006 specification, which was a revise of the ZigBee 2004 specification.
In the year 2007, the ZigBee established the ZigBee and the ZigBee PRO characteristics sets.
The ZigBee describes the three foremost kinds of the devices: the coordinator, router, and end device. Moreover, the devices can perform as a trust center or gateway.
The coordinator is a full-function device (FFD). It carries out the important function of managing the network, beginning a network, and allowing other devices to connect or exit the network.
The trust center carries out the authentication of devices connecting the network, security management, and key distribution.
The ZigBee wireless technology presents star, tree, and mesh topologies.
The ZigBee wireless technology operates the layer architecture for its protocol.
The ZigBee wireless technology operates IEEE 802.15.4 for its physical and MAC layers.
The ZigBee wireless technology protocol architecture is made up of the application, application support sublayer, and network layers
The ZigBee wireless technology direct, group, and broadcast addressing.
A ZigBee end device can consists of 240 endpoints, whereby every one of the endpoint may stand for various application.
The ZigBee PRO operates a mesh topology, and it is a beaconless network.
The ZigBee PRO supplies stochastic addressing, group addressing, asymmetric links, fragmentation, and frequency agility.
The ZigBee PRO supplies many-to-one routing and multicast routing.
The ZigBee PRO supplies standard and high-security modes.
The ZigBee PRO security level is set to 5.
The ZigBee PRO offers the link management.
The ZigBee PRO end devices are only powered by battery.
The ZigBee 2007 specification supports tree and mesh topologies.
The ZigBee PRO chooses the finest channel at start-up and when in operation.
Conclusion
The Zigbee wireless technology is programmed in a chip form and is operated in a lot electronic devices to carry out tasks automatically. The wireless technology is operated on in order to control and monitor. The wireless technology centralizes all of the units in one place and allows the remote monitoring.
A home can be centralized by maximizing the security feature. A lot of tiny equipments are showing up with embedded Zigbee wireless technology chips and functions extraordinarily.
The Zigbee wireless technology is slowly but surely triumph the market by presenting electronic devices such as:
smoke sensor/detector
heat sensor
medical and scientific equipments
control units of home and industry
wireless communication devices
The rising turn in the sector of technology with the coming of the ZigBee wireless technology; the very close coming future of the Zigbee wireless technology is truly promising to succeed in almost every walk of life.
Moving on, the ZigBee wireless technology means of digital communication system is inexpensive and implements the use of the batteries. The wireless technology can be operated in a various circumstances.
The wireless technology is aiming the control applications industries that don't need high data rates, and have low power, inexpensive and simple to operate.
The ZigBee mesh is capable of managing lot of user nodes plus one fully functional device. Furthermore, the devices are optimized for expanded battery life.
